There are some extent that needs prayers mate. Yes gambling addiction is not related to spiritual, but you may need some spiritual help to assist in both prayers for the affected person. Someone addicted to the extent that he lost all his life to gambling or may be someone who planned to kill himself because of loss, should be prayed for and consoled. I know my own analogy might be a bit different from many others here on this thread but you can combine different hands to help an addicted individual. Addiction is a physical effect but to some extent might need a spiritual help..
I get your point but i hope you understand that your prayers is like a waste of energy if the gambler your praying for is not determined to change, if prayer js the core solution to that problem do you think addiction would've existed in the first place? Don't you think people would prayed that nobody should get addicted anymore? Yes a spiritual father can play a good role cause they're highly respected in our society, so they can preach and guide their followers against that path and even advice them when things get tough or direct them to the rightful places for medication, and not being the primary solution to gambling addiction, what a victim of addiction needs is to visit a therapist then go for rehabilitation for proper medications.